|You threw a Titan to the ground. With nothing but human strength. I saw that, and realized...you can't save anyone without power.|
|— Louise tells Mikasa Ackerman of how she inspired her|
Louise (ルイーゼ Ruīze?) is a member of the Yeagerists. Once a young girl who was in Trost with her mother when the Titans invaded, she later joins the military and participates in the Raid on Liberio as a Survey Corps recruit (新兵 Shinpei?). She defects from the Corps to join Eren Yeager's cause.
Louise has shoulder-length light hair which she keeps parted down the middle. When she was younger, her outfit consisted of a jacket which she wore over a dark shirt and skirt. Her current civilian clothes consist of a simple light long-sleeve shirt and a long skirt. When on duty, she can be seen wearing the standard Survey Corps uniform.
Louise believes that strength is the most important attribute one can have in the world, to the point that she almost seems to have a "might equals right" mentality. Much of this mindset stems from her experiences during the Battle of Trost District, where she claims to have learned from watching Mikasa Ackerman fight in the face of adversity to achieve victory. She believes that the ends justify the means, and has no qualms about breaking rules if she believes that disobeying others will get her what she wants.
Louise is among the many citizens who are trapped inside the city because Dimo Reeves, a merchant and the head of the Reeves Company, was barring the gate with his cargo. Louise's mother assures her that her father will kill the Titans with cannons, but Louise spots an Abnormal Titan charging towards them. The Titan is quickly slain by Mikasa Ackerman. Afterward, Mikasa threatens to kill Reeves, who then orders his men to remove the carriage blocking the gate. As the citizens leave Trost, Louise and her mother express their gratitude towards Mikasa before she leaves to rejoin the battle. Mikasa salutes them and Louise, ecstatic, salutes back.
Seeing a Titan felled by human strength alone, Louise is inspired to join the military as well. At some point, Louise joins the Survey Corps in order to get closer to Mikasa, whom she has come to idolize.
In the year 854, Louise is one of the Survey Corps members who participate in the infiltration and attack in Liberio. Amid the conflict, Louise watches Eren unsuccessfully attempt to devour the War Hammer Titan and later takes cover from the Beast Titan's projectiles. She tries to assist Jean in killing the Cart Titan's operator, but is forced to flee by Theo Magath and other Marleyan soldiers. As the airship arrives, she joins the rest of the Survey Corps in retreating along its path.
As the Survey Corps makes its retreat from Liberio, Louise and the surviving soldiers celebrate their overwhelming victory against Marley. As they are celebrating, two children board the Corps' airship and open fire, gravely injuring Sasha Blouse. While the rest of the soldiers begin to savagely beat the children, Louise tries to help stabilize Sasha and keep her alive, to no avail.
When the Corps returns to Paradis, Eren is arrested for acting against orders. Unhappy with Eren's treatment, Louise is among a handful of soldiers who leak the information of Eren's arrest to the public to try to force the military to release Eren. After they are found out, Hange Zoë arrests Louise and her compatriots as well.
Mikasa takes Louise to the cell she will be staying in, and Louise is disappointed to learn she will not be staying in the same cell that Mikasa was imprisoned in. Louise tells Mikasa that she does not regret spilling the secrets of Eren's arrest to the press, explaining that she has believed ever since Trost that one must be ready to fight when threatened. Louise tries to appeal to Mikasa to help free Eren, but Mikasa coldly cuts her off. As Mikasa leaves, Louise salutes her.
The rebels are freed from their cells by guards who have also sided with Eren, and rendezvous with Eren himself outside of the city. Eren declares that his next objective will be to locate Zeke Yeager.
Louise later appears along with a number of armed Yeargerists at a restaurant. They attempt to obtain information as to the whereabouts of Zeke Yeager from the Survey Corps Commander. Afterward, the group departs to the Shiganshina District alongside their captives including several officers of the Survey Corps.
When Marley's forces launch a retaliatory attack against Shiganshina, the Yeagerists are forced to release their imprisoned soldiers so that they will have extra manpower. Louise visits Mikasa to let her know that she is happy to be fighting alongside her again, although Mikasa is unconcerned. Noticing that Mikasa has left her scarf, Louise decides to wear it herself.
Louise is among the Yeagerists Jean Kirstein leads in a defense around the military's headquarters against Zeke's newly-transformed Titan horde. During the fighting a shard from a Thunder Spear is embedded in Louise's stomach, fatally wounding her.
While she is in the hospital, Louise is visited by Mikasa. Louise laments that she will not be able to see the fruition of Eren's plan and mentions that she got to speak to him once about Mikasa. She claims that Eren told her to throw Mikasa's scarf away and that she instead chose to wear it herself, prompting Mikasa to demand she gives it back. As Mikasa leaves Louise says she has no regrets in life and she lived devoting her heart.
- Mikasa Ackerman - As a child, Louise and her mother's lives were saved by Mikasa during the Battle of Trost. After this, she began idolizing Mikasa, which ultimately became her primary reason for joining the Survey Corps. However, their conflicting ideologies and goals have caused Mikasa to treat her indifferently, unsure of where Louise's true loyalties lie. Nevertheless, Louise continues to look up to Mikasa for strength and leadership.
- Eren Yeager - Although she does not appear to be as devoted to Eren as some of the other rebels, Louise still believes that Eren will be the one who will save Paradis and is willing to follow him instead of the military. She believes in Eren's strength enough that she is willing to endanger herself by going against the military.
- Three members of the Panzer Unit